Bump webpack in /jupyterlab/tests/mock_packages/test-hyphens-underscore (#17495)

Bumps [webpack](https://github.com/webpack/webpack) from 5.91.0 to 5.99.6.
- [Release notes](https://github.com/webpack/webpack/releases)
- [Commits](webpack/webpack@v5.91.0...v5.99.6)

---
updated-dependencies:
- dependency-name: webpack
  dependency-version: 5.99.6
  dependency-type: indirect
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]